Ultrasound mesh localization for interactive systems

ABSTRACT

In general, techniques are described for locating a user using an ultrasound mesh. The techniques may be performed by an interactive system comprising one or more processors. The processors may be configured to determine an amplitude of a first ultrasound signal emitted by one or more transducers and received by a microphone. This first ultrasound signal may be of a first frequency. The processors may then determine an amplitude of a second ultrasound signal emitted by the one or more transducers and received by the microphone. The second ultrasound signal may be of a second frequency different from the first frequency. The processors may be further configured to determine a location of the microphone relative to the one or more transducers based at least on the determined amplitude of the first ultrasound signal and the determined amplitude of the second ultrasound signal.

TECHNICAL FIELD

In general, the techniques described in this disclosure relate to audiolocalization and, more particularly, audio localization using anultrasound mesh.

BACKGROUND

Generally, interactive systems commonly locate a user or a user-operatedsensor using light. For example, some video game systems may utilize aninfrared light sensor to locate a controller that emits infrared lightsignals. Alternative video game systems may utilize a camera to captureimages (based on received light), processing these images to locate auser or a user operated controller (where the controller emits a lightof a certain color (or wavelength) that facilitates locating the useroperated controller). However, these light-based interactive systems areoften expensive given the processing resources required to adequatelylocate a user or a user-operated sensor. Moreover, these light-basedinteractive systems often require a clear line of site between thecamera or other light-sensing device and the user or user-operatedsensor that may prohibit (often due to impractically large spacerequirements) more than two users from interacting with the light-basedinteractive system.

SUMMARY

In general, the techniques described in this disclosure provide forlocalization of a user or user-operated sensor using an ultrasound mesh.That is, one or more transducers, such as a speaker, may emit one ormore ultrasounds, each at a different ultrasonic frequency, to form whatmay be referred to as an “ultrasound mesh.” Within this mesh, amicrophone or other audio capture device may capture each of theultrasounds. In some instances, the microphone may then analyze thecaptured ultrasounds to identify the location of a user associated withthe microphone, reporting this location back to a localization device orsystem. In other instances, the microphone may provide the capturedultrasound or characteristics of the captured ultrasound (e.g., thefrequency and gain) to the localization device. By enabling audiolocalization using an ultrasound mesh, the techniques may reduceprocessing requirements and thereby potentially reduce costs, while alsopotentially enabling detection of a user or user-operated sensor withoutrequiring a clear line of site between the localization device and theuser or user-operated sensor.

In one aspect, a method comprises determining an amplitude of a firstultrasound signal emitted by one or more transducers and received by amicrophone, where the first ultrasound signal is of a first frequency.The method further comprises determining an amplitude of a secondultrasound signal emitted by the one or more transducers and received bythe microphone, where the second ultrasound signal is of a secondfrequency different from the first frequency. The method also comprisesdetermining a location of the microphone relative to the one or moretransducers based at least on the determined amplitude of the firstultrasound signal and the determined amplitude of the second ultrasoundsignal.

In another aspect, an interactive system comprises one or moreprocessors configured to determine an amplitude of a first ultrasoundsignal emitted by one or more transducers and received by a microphone,wherein the first ultrasound signal is of a first frequency, determinean amplitude of a second ultrasound signal emitted by the one or moretransducers and received by the microphone, wherein the secondultrasound signal is of a second frequency different from the firstfrequency, and determine a location of the microphone relative to theone or more transducers based at least on the determined amplitude ofthe first ultrasound signal and the determined amplitude of the secondultrasound signal.

In another aspect, an interactive system comprises means for determiningan amplitude of a first ultrasound signal emitted by one or moretransducers and received by a microphone, where the first ultrasoundsignal is of a first frequency. The interactive system also comprisesmeans for determining an amplitude of a second ultrasound signal emittedby the one or more transducers and received by the microphone, where thesecond ultrasound signal is of a second frequency different from thefirst frequency. The interactive system further comprises means fordetermining a location of the microphone relative to the one or moretransducers based at least on the determined amplitude of the firstultrasound signal and the determined amplitude of the second ultrasoundsignal.

In another aspect, a non-transitory computer-readable storage medium hasstored thereon instructions that, when executed, cause one or moreprocessors of an interactive system to determine an amplitude of a firstultrasound signal emitted by one or more transducers and received by amicrophone, determine an amplitude of a second ultrasound signal emittedby the one or more transducers and received by the microphone, anddetermine a location of the microphone relative to the one or moretransducers based at least on the determined amplitude of the firstultrasound signal and the determined amplitude of the second ultrasoundsignal. The first ultrasound signal is of a first frequency, while thesecond ultrasound signal is of a second frequency different from thefirst frequency.

The details of one or more aspects of the techniques described in thisdisclosure are set forth in the accompanying drawings and thedescription below. Other features, objects, and advantages of thetechniques will be apparent from the description and drawings, and fromthe claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating an interactive system that mayperform various aspects of the techniques described in this disclosureto locate a microphone associated with a user using an ultrasound mesh.

FIG. 2 is a block diagram illustrating an example of the interactivesystem of FIG. 1 in more detail when interfacing with a user-operateddevice that includes the microphone also shown in the example of FIG. 1.

FIG. 3 is a diagram illustrating the computation of the location by oneof the user-operated device or the interactive system shown in theexamples of FIGS. 1 and 2 with respect to two speakers.

FIG. 4 is a diagram illustrating the computation of the location by oneof the user-operated device or the interactive system shown in theexamples of FIGS. 1 and 2 with respect to three speakers.

FIG. 5 is a flow chart illustrating exemplary operation of one of theinteractive system or the user-operated device of FIGS. 1 and 2 inperforming the techniques described in this disclosure.

FIG. 6 is a diagram illustrating an exemplary three-dimensional (3D)video data viewing system in which various aspects of the techniquesdescribed in this disclosure may be performed.

FIG. 7 is a flowchart illustrating exemplary operation of theinteractive system and the shutter glasses of FIG. 6 in perform variousaspects of the techniques described in this disclosure.

FIG. 8 is a diagram illustrating an exemplary classroom system that mayperform various aspects of the techniques described in this disclosure.

FIG. 9 is a flowchart illustrating exemplary operation of the classroomsystem of FIG. 8 in performing various aspects of the techniquesdescribed in this disclosure.

FIG. 10 is a diagram illustrating an exemplary airline system that mayperform various aspects of the techniques described in this disclosure.

FIG. 11 is a flowchart illustrating exemplary operation of the airlinesystem of FIG. 10 in performing various aspects of the techniquesdescribed in this disclosure.

DETAILED DESCRIPTION

FIG. 1 is a block diagram illustrating an interactive system 10 that mayperform various aspects of the techniques described in this disclosureto locate a microphone 14 associated with a user 12 using an ultrasoundmesh. The interactive system 10 may generally represent a systemcomprising one or more devices that may interface with speakers 16A and16B (“speakers 16”) to emit ultrasounds of one or more ultrasonicfrequencies to locate the microphone 14 in order to interact with theuser 12. Examples of the interactive system 10 may comprise atwo-dimensional (2D) television, a three-dimensional (3D) television, aso-called “smart television,” a gaming system, a portable gaming system,a tablet computer, a laptop computer, a workstation, a desktop computer,a mobile phone, a so-called “smart phone,” a digital video disc (DVD)player, a high-definition disc player, a personal media player, anyother type of device with which the user 12 may interact or anycombination of one or more of these types of devices.

The speakers 16 may each represent a transducer that converts electricalsignals into sound. Although shown as separate from the interactivesystem 10, the interactive system 10 may include the speakers 16 asintegrated components (meaning that the speakers 16 are included withinthe interactive system 10, often being integrated into the housing ofthe interactive system 10). In some instances, the speakers 16 may eachcomprise a speaker specifically configured to output ultrasounds. Inother instances, the speakers 16 may each comprise a speaker that iscapable of emitting sounds over a wide range of frequencies, includingultrasonic frequencies.

While shown as being arranged to emit ultrasounds 17A and 17B(“ultrasounds 17,” which may also be referred to as “ultrasound beams17”), respectively, in particular directions in the example of FIG. 1,the speakers 16 may be arranged in various configurations, such as ahorizontal or vertical array of speakers, different than that shown inthe example of FIG. 1. The speakers 16, when arranged, for example, inan array configuration, may all emit ultrasounds in a single samedirection. In these configurations, the interactive system 10 maygenerate audio signals that are sent to the speakers 16 that facilitatebeam forming so that the speakers 16 may form beams of ultrasounds thatare effectively emitted in different directions to facilitate thelocalization of the microphone 14, as described below in greater detail.

The microphone 14 may represent any type of device capable of capturingsound. The microphone 14 may generally represent any type ofacoustic-to-electric transducer or sensor that is capable of convertingsound into an electrical signal. There are a number of different typesof microphones, each of which varies in the way the different types ofmicrophones capture sound. To provide a few examples, the microphone 14may include a dynamic microphone (which refers to a microphone thatcapture sound using electromagnetic induction), a condenser microphone(which refer to a microphone that capture sound using capacitancechange), and a piezoelectric microphone. While shown as the microphone14, the microphone 14 may be incorporate within or internal to anotherdevice, such as a remote control, 3D glasses used for viewing a 3Dtelevision, a video game controller, an identification tag, a name tag,a shirt pin, a cellular phone, a so-called “smart phone,” a laptopcomputer, a tablet computer, or any other portable or mobile device.

In general, interactive systems commonly locate a user or auser-operated sensor using light. For example, some video game systemsmay utilize an infrared light sensor to locate a controller that emitsinfrared light signals. Alternative video game systems may utilize acamera to capture images (based on received light), processing theseimages to locate a user or a user operated controller (where thecontroller emits a light of a certain color (or wavelength) thatfacilitates locating the user operated controller).

In the context of video game systems, often the video game systemrequires extensive processing capabilities to accurately identify thelocation of the controller and/or user, especially in the case where acamera is used to identify not just a user but the various appendages orother aspects of the user. In this sense, light-based user and/or useroperated localization processes may not facilitate low cost localizationof users and/or user operated sensors, which may prevent suchlight-based localization processes from being adopted in certaincontexts.

Moreover, in some camera-based localization systems, the ability toidentify three or more users without the aid of a light-based controlleror other sensor may be difficult or impractical. For example, when threeor more users are present, the users may need to be farther back fromthe camera so that each user does not overlap one another in an image orframe, making such camera-based localization system impractical forstandard room settings. In this example, if the users stand closertogether or partially in front of one another, the camera-basedlocalization system may recognize only two users. The inability orimpracticality of camera-based localization systems may prevent adoptionin certain contexts.

Even overlooking the drawbacks of camera-based localization systems,most light-based localization systems suffer from spurious signals thatmay distort or result in misidentification of a user or user-operatedcontroller. For example, an infrared remote control that is notassociated with a video game system may generate signals that may beperceived by the video game system as originating from a controllerassociated with the video game system. The video game system may thenlocate the remote control and use the location of the remote control asthe location of the controller, which may result in random or erraticgame play. Likewise, in camera-based localization systems, bright lightsor insufficient contrast between users and background may generate noisethat resembles a controller or masks a user, leaving the video gamesystem to interpret this noise in random ways that results, again, inrandom or erratic game play.

In accordance with the techniques described in this disclosure, a formof localization that relies on sound may be implemented in a number ofdifferent contexts to facilitate the localization of a microphone,which, depending on the context, may be associated with a user.Generally, the techniques may involve determining an amplitude of afirst ultrasound signal emitted by one or more transducers (e.g., thespeakers 16) and received by the microphone 14. This first ultrasoundsignal is typically at a specified frequency or within a specified rangeof frequencies. Additionally, the techniques may include determining anamplitude of a second ultrasound signal emitted by one or more of thespeakers 16 and received by the microphone 14. This second ultrasoundsignal is of a second frequency or range of frequencies that is oftendifferent from the first frequency or range of frequencies. Based onthese determined amplitudes, a location of the microphone 14 relative tothe speakers 16 can be determined.

To illustrate, the interactive system 10 may, as shown in the example ofFIG. 1, interface with the speaker 16A, providing an electrical signalto the speaker 16A that causes the speaker 16A to emit the ultrasound17A at ultrasonic frequency, f₁. The interactive system 10 may alsointerface with the speaker 16B, providing an electrical signal to thespeaker 16B that causes the speaker 16B to emit the ultrasound 17B atultrasonic frequency, f₂. Assuming the user 12 and the microphone 14associated with the user 12 are located at the location denoted“Microphone Position 1” in the example of FIG. 1, the microphone 14 maycapture audio signals as shown in the corresponding the graph 18A. Thex-axis of the graph 18A denotes frequency (as measured in Hertz (Hz)),while the y-axis of the graph 18A denotes amplitude in terms of decibels(dB).

As shown in the graph 18A, the microphone 14 captures an audio signalhaving a greater amplitude for signal one (1) having a frequency equalto f₁ than for signal two (2) having a frequency equal to f₂. In otherwords, ultrasounds are more tightly focused than other types of soundshaving lower frequencies. For this reasons, ultrasounds may becharacterized as ultrasound beams. Using two or more ultrasound beams ofthis type may enable the interactive system 10 to form what is referredto in this disclosure as an “ultrasound mesh.” An ultrasound mesh may,in this disclosure, refer to two or more ultrasounds (or ultrasoundbeams) that cover a given area.

When the microphone 14 is moved within this ultrasound mesh, the audiocaptured by the microphone 14 may exhibit certain characteristics thatfacilitate localization of the microphone 14. That is, becauseultrasounds have a high frequency and corresponding short wavelengths,the amplitude of the signal may change with respect to different sensingangles, with the highest amplitude occurring on-axis to the direction ofthe ultrasound beam or, in other words, directly in front of thespeaker. The amplitude also varies depending on how close the microphoneis to each of the speakers.

To continue the illustration of how the techniques utilize thisultrasound mesh to locate the microphone 14, it is assumed that the user12 moves the microphone 14 to the position denoted “microphone position2” in the example of FIG. 1 from microphone position 1. When in themicrophone position 2, the microphone 14 is off-axis to the ultrasound17A emitted by the speaker 16A and off-axis to the ultrasound 17Bemitted by the speaker 16B. Moreover, when in the microphone position 2,the microphone 14 is approximately equidistant from the speakers 16. Theresulting signal sensed by the microphone is shown in graph 18B, wherethe signal has approximately the same amplitude at the first frequencyf₁ as at the second frequency f₂.

When the microphone 14 is positioned in the position denoted “microphoneposition 3” in the example of FIG. 1, the microphone 14 is off-axis tothe ultrasound beam 17A emitted by the speaker 16A, but on-axis to theultrasound beam 17B emitted by the speaker 16B, while also being moreproximate to the speaker 16B than to the speaker 16A. The resultingsignal sensed by the microphone 15 and shown in a graph 18C maytherefore have a higher amplitude at the second frequency f₂ (relativeto the amplitude at f₁) and a lower amplitude at the first frequency f₁(relative to the amplitude at f₂). In this way, the interactive system10 and/or the microphone 14 may determine, based on the amplitude ofthese frequencies or, more specifically, a ratio of the amplitude ofthese frequencies, a location of the microphone 14 (e.g., the frequencyand amplitude may specify whether the microphone is in the first, secondor third positions denoted as microphone positions 1, 2 and 3 in theexample of FIG. 1).

In other words, when several of these speakers 16 are assembled in theinteractive device 10, each emitting beams with different frequenciesinto different directions in space, the techniques may facilitate thecreation of an ultrasound mesh. At each “node” of the mesh, themicrophone 14 may be on axis to one of the ultrasound beams. When themicrophone 14 is placed at these locations, the microphone 14 may pickup the strongest amplitude for the signal with corresponding frequencyfrom the corresponding one or more of the speakers 16. At the same time,the microphone 14 may also pickup off-axis amplitude of signals withother frequencies from other ones of the speakers 16. When themicrophone 14 is located in angles between different ones of thespeakers 16, the relative amplitude of different frequency tones willvary accordingly, and the relative amplitude combinations may beprocessed to indicate the current angle of the microphone 14.

In operation, the interactive system 10 may determine an amplitude of afirst ultrasound signal emitted by one or more transducers and receivedby a microphone, where the first ultrasound signal is of a firstfrequency. The interactive system 10 may also determine an amplitude ofa second ultrasound signal emitted by the one or more transducers andreceived by the microphone, where the second ultrasound signal is of asecond frequency different from the first frequency. As described inmore detail below, the interactive system 10 may then determine alocation of the microphone relative to the one or more transducers basedat least on the determined amplitude of the first ultrasound signal andthe determined amplitude of the second ultrasound signal.

Likewise, in some examples, the microphone 14 may determine an amplitudeof a first ultrasound signal emitted by one or more transducers andreceived by a microphone, where the first ultrasound signal is of afirst frequency. The microphone 14 may also determine an amplitude of asecond ultrasound signal emitted by the one or more transducers andreceived by the microphone, wherein the second ultrasound signal is of asecond frequency different from the first frequency. As described inmore detail below, the microphone 14 may then determine a location ofthe microphone relative to the one or more transducers based at least onthe determined amplitude of the first ultrasound signal and thedetermined amplitude of the second ultrasound signal.

When the location of the microphone 14 is determined by the interactivesystem 10, the interactive system 10 may utilize this determinedlocation to facilitate interaction with the user 12, whether suchinteraction involves adapting or otherwise modifying 3D video contentbased on this determined location, adapting or otherwise modifyingbehavior of a game or other activity in which user 12 is participating,or presenting information or user interfaces specific to user 12 inresponse to the determined location to provide a few examples.

When the location of the microphone 14 is determined by the microphone14, the microphone 14 may provide the determined location to theinteractive system 10. The interactive system 10 may then utilize thisdetermined location to facilitate interaction with the user 12 in theexemplary ways described above or any other ways by which suchinteractive systems may interact with the user 12.

In this manner, the techniques described in this disclosure may providefor localization of a user or user-operated sensor using an ultrasoundmesh. That is, one or more transducers, such as the speakers 16, mayemit the ultrasounds 17, each at a different ultrasonic frequency, toform what may be referred to as an “ultrasound mesh.” Within this mesh,the microphone 14 or other audio capture device may capture each of theultrasounds 17. In some instances, the microphone 14 may then analyzethe captured ultrasounds to identify the location of the user 12associated with the microphone 14, reporting this location back to alocalization device or system. In other instances, the microphone 14 mayprovide the captured ultrasound or characteristics of the capturedultrasound (e.g., the frequency and gain) to a localization device, suchas the interactive system 10. By enabling audio localization using anultrasound mesh, the techniques may reduce processing requirements andthereby potentially reduce costs, while also potentially enablingdetection of a user or user-operated sensor without requiring a clearline of site between the interactive system 10 and the user 12 oruser-operated sensor device that includes the microphone 14.

FIG. 2 is a block diagram illustrating an example of the interactivesystem 10 of FIG. 1 in more detail when interfacing with a user-operateddevice 30 that includes the microphone 14 also shown in the example ofFIG. 1. In the example of FIG. 2, the interactive system 10 includes acontrol unit 32, speakers 16A-16N (“speakers 16,” where each of thespeakers 16A-16N may be substantially similar to or the same as thespeakers 16A and 16B described above with respect to the example ofFIG. 1) and an interface 34.

The control unit 32 may represent one or more processors (not shown inFIG. 1), e.g., a central processing unit (CPU) and/or graphicalprocessing unit (GPU), that execute software instructions, such as thoseused to define a software or computer program, stored to anon-transitory computer-readable medium (again, not shown in FIG. 1),such as a storage device (e.g., a disk drive, or an optical drive), ormemory (such as Flash memory, random access memory or RAM) or any othertype of volatile or non-volatile memory, that stores instructions tocause the one or more processors to perform the techniques describedherein. Alternatively, the control unit 32 may represent dedicatedhardware, such as one or more integrated circuits, one or moreApplication Specific Integrated Circuits (ASICs), one or moreApplication Specific Special Processors (ASSPs), one or more FieldProgrammable Gate Arrays (FPGAs), one or more digital signal processors(DSPs), or any combination of one or more of the foregoing examples ofdedicated hardware, for performing the techniques described herein. Thecontrol unit 32 may, in some instances, represent a combination ofdedicated hardware and one or more processors that execute softwareinstructions.

The interface 34 may represent an interface capable of communicating viaany form of proprietary, standardized or openly-defined communicationprotocol. The interface 34 may represent a physical interface capable ofcommunicating either via a wire or other physical communication mediumsor wirelessly. The interface 34 may, for example, communicate wirelesslyvia one or more the Institute of Electrical and Electronics Engineers802.11 set of standards, such as IEEE 802.11a, 802.11b, 802.11g,802.11n, each of which defines protocols for a wireless wide areanetwork (WAN). In addition or as an alternative to this form of wirelessWAN, the interface 34 may communicate wirelessly via a wireless personalarea network (WPAN), such as those based off of or defined in the IEEE802.15.

The user-operated device 30 includes a control unit 36, a microphone 14(which may be substantially the same as microphone 14 shown as astand-alone microphone in the example of FIG. 1) and an interface 40.The control unit 36 may be substantially similar to the control unit 32described above in terms of what the control unit 36 may represent inthe example of FIG. 2 (referring generally to the above described one ormore processors, dedicated hardware or some combination thereof). Theinterface 40 may also be substantially similar to interface 34 in termsof what the interface 40 may represent in the example of FIG. 2.

As further shown in the example of FIG. 2, the control unit 32 ofinteractive system 10 may include an ultrasound beam forming module 42,a location determination module 44 and a location-based processingmodule 46. The ultrasound beam forming module 42 may represent a modulethat generates audio signals 47, which when provided or fed to thespeakers 16 cause the speakers 16 to emit ultrasound beams, such asultrasound beams 17 shown in the example of FIG. 1. The ultrasound beamforming module 42 may generate audio signals having an ultrasonicfrequency and then perform signal processing to control the phase and/orthe relative amplitude of the signal at each of the speakers 16 in orderto create a pattern of constructive and destructive interference in theaudio wavefront emitted by the speakers 16. This beam forming may, inthis sense, represent a form of spatial filtering, where the audiosignals 47 for each of the speakers 16 are filtered such that whenplayed by the speakers 16 the wavefront of the audio emitted by thespeakers 16 forms what may be characterized as a “beam.”

In this respect, the beam forming module 42 may process the firstultrasound signal 47 prior to providing the first ultrasound signal 47to the speakers 26 (which may, as noted in this disclosure, be arrangedin an array) so as to generate a first directional ultrasound signal 47that, when emitted by the speakers 16 in the array, appears to bedirected in a first direction. The ultrasound beam forming module 42 mayalso processing the second ultrasound signal 47 prior to providing thesecond ultrasound signal 47 to the speakers 16 in the array so as togenerate a second directional ultrasound signal 47 that, when emitted bythe speakers 16 in the array, appears to be directed in a seconddirection. The ultrasound beam forming module 42 may then concurrentlyprovide the first and second directional ultrasound signals 47 to thespeakers 16 in the array such that the speakers 16 in the arrayconcurrently emit the first and second direction ultrasound signals(such as ultrasound beams 17 shown in the example of FIG. 1) as thefirst and second ultrasound signals.

The location determination module 44 may represent a module thatdetermines a location of the user-operated device 30 and, morespecifically, the microphone 14. The location determination module 44may receive location information 49 via the interface 34 from theuser-operated device 30. In some instances, this location information 49may include the location of microphone 14 as computed by theuser-operated device 30 based on audio signals 51 captured by themicrophone 14. Reference to the location of microphone 14 may refer tothe location of the microphone 14 as measured relative to the speakers16, as is described in more detail below.

In any event, the location determination module 44 may, in thisinstance, represent a module that determines the location of themicrophone 14 by receiving the location information 49. In this sense,the location information 49 may include the location 53, which wascomputed by the microphone signal processing module 53 and specified asat least a portion of the location information 49. The locationinformation 49 may further include a code, identifier or other data toindicate that the location information 49 corresponds to theuser-operated device 30 or the user operating the user-operated device30. The location determination module 44 may, upon receiving thelocation information 49 specifying the location of the user-operateddevice 30, perform further processing to refine the location informationbased, for example, on previously received location information 49. Thatis, the location determination module 44 may compute an average locationover the last couple of iterations of receiving the location information49 (which may be, as an example, an average location over the lastcouple of tens of minutes, minutes, seconds, and/or millisecondsdepending on the context in which interactive system 10 is employed).

In some instances, the location information 49 may specify either thecaptured audio signals 51 (captured at the microphone 14 of theuser-operated device 30), a processed form of captured audio signals 51(e.g., a compressed form of captured audio signals), or some otherprocessed form of captured audio signals 51 (e.g., ratios of amplitudesof the captured audio signals, which is, as described below in moredetail indicative of the location of the microphone 15). In theseinstances, the location information 49 represents information thatspecifies the location of the microphone 14 in an unprocessed orpre-processed form, but that does not explicitly specify the location ofthe microphone 14. The location determination module 44, in theseinstances, may represent a module that computes the location of themicrophone 14 based on the location information 49 using various aspectsof the techniques described in more detail below.

Briefly, the location determination module 44 may perform some form offrequency analysis, such as a fast Fourier transform (FFT), or othersignal processing to determine an amplitude at various frequencies. Thelocation determination module 44 may compare the amplitude at variousfrequencies to determine a ratio between an amplitude at one frequencyand an amplitude at a different frequency (where each frequency may beassociated with a different speaker). Based on this ratio, the locationdetermination module 44 may determine the location 53 (as evidenced bythe graphs 18 shown in the example of FIG. 1).

The location-based processing module 46 represents a module thatreceives the location 53 determined by location determination module 44and processes the location to perform some action (at least some of thetime) in response to receiving the location 53. The location-basedprocessing module 46 may, for example, process the location 53 todetermine whether to adjust playback of three-dimensional video data(such as when a viewer operating or wearing the user-operated device 30moves beyond a relocation threshold). The location-based processingmodule 46 may, as another example, determine when a user operating theuser-operated device 30 is proximate (within some proximity threshold)to the interactive system 10 or some component of the interactive system10 in which the speakers 16 are located. Further examples of the contextin which the interactive system 10 may be employed are described belowwith respect to the examples of FIGS. 6-11.

While described as being included within the interactive system 10, thelocation-based processing module 46 may be included within any device towhich the interactive system 10 is included as a component of thisdevice or may be included within any device to which the interactivesystem 10 may interface as a component of this device. In other words,the interactive system 10 may not include the location-based processingmodule 46 but may represent a system by which a location of themicrophone 14 is determined. The interactive system 10 may then providethis location to any form of location-based processing module of anydevice to which the interactive system 10 interfaces, whether theinteractive system 10 is internal to or incorporated within or externalfrom this device. The techniques described in this disclosure shouldtherefore not be limited in this respect to the examples provided inthis disclosure.

The control unit 36 of the user-operated device 30 may include amicrophone signal processing module 48. The microphone signal processingmodule 48 may represent a module that processes captured audio signals51 to generate the location information 49. As noted above, themicrophone signal processing module 48 may process the captured audiosignals 51 to compute the location of the microphone 14. IN someinstances, rather than compute this location, the microphone signalprocessing module 48 may process the captured audio signals 51 togenerate location information 49 that includes the captured audiosignals 51, a compressed form of the captured audio signals 51 and/orsome derivative thereof.

In operation, the control unit 36 of the user-operated device 30 mayregister with the interactive system 10 (often automatically uponpowering on or activating the user-operated device 30 and assuming theinteractive system 10 is already powered on or activated). The controlunit 36 may register with the interactive system 10 by sending aregistration code or other registration information, whereupon theinteractive system 10 may begin generating the audio signals 47 (whennot already generating audio signals 47). The speakers 16 may thenoutput audio based on the audio signals 47.

The microphone 14 of the user-operated device 30 may sense, detect orotherwise capture the sound audio signals 47, generating the capturedaudio signals 51 (which may differ from the audio signals 47 due tonoise or other interference). The control unit 36 may then invoke themicrophone signal processing module 48 to process the captured audiosignals 51. The microphone signal processing module 48 may perform anyform of signal processing often to reduce residual noise orinterference. The microphone signal processing module 48 may performtransforms with respect to the captured audio signals 51 so as totransform, such as a discrete cosine transform (DCT), the captured audiosignals from a spatial domain to a frequency domain. The microphonesignal processing module 48 may, in this way, represent a module thatmay perform any form of signal processing to improve the quality of orotherwise alter the captured audio signals 51. The microphone processingmodule 51 may then generate the location information 49 in one or moreof the various ways described above, providing this location information49 to the interface 40.

As noted above, the user-operated device 30 may register with theinteractive system 10. Part of this registration process may involveestablishing one or more communication channels 50 via a wired orwireless protocol, such as any of those described above. Theuser-operated device 30 may establish these communication channels 50 aspersistent channels that remain active as long as the user-operateddevice 30 and the interactive system 10 are operational. Alternatively,the user-operated device 30 may establish these communication channels50 for set durations or as required, such as in response to receivingthe location information 49. In any event, the interface 40 maycommunicate the location information 49 via the communication channel 50to interface 34 of the interactive system 10.

The interface 34, upon receiving this location information 49, maytransmit this location information 49 to the location determinationmodule 44. The location determination module 44 may then determine thelocation 53 in any of the various ways described above, transmittingthis location 53 to the location-based processing module 46. Thelocation-based processing module 46 may then process this location 53 toperform any of the actions described in this disclosure.

FIG. 3 is a diagram illustrating the computation of the location 53 byone of the user-operated device 30 or the interactive system 10 shown inthe examples of FIGS. 1 and 2 with respect to two speakers 16A and 16B.That is, as described above, either the system 10 or the device 30 maycompute, based on the captured audio signals 51 or some derivativethereof, the location 53. While described below as being computed by thesystem 10, the computation aspects of the techniques may be performeddevice 30 or possibly some intervening device, such as a dongle devicethat interfaces with the interactive system 10 or the user-operateddevice 30.

In the example of FIG. 3, the location determination module 44 maycompute location with respect to two speakers, which may represent thespeakers 16A and 16B shown in the example of FIG. 1. The locationdetermination module 44 may be configured to know the distance, d,separating the speaker 16A from the speaker 16B. Typically, the distanced is specified as the distance from the center point of the speaker 16Aand the center point of the speaker 16B. Often, this distance d isstatic and does not fluctuate, especially when speaker arrays are usedthat include a line of two or more speakers set as specific distances d.In some instances, the user may interface with the interactive system 10to specify the distance d, where the user may have to physically measuredistance d. Typically, the user has to specify the distance d only whenthe speaker positions are unknown. In some instances, the interactivesystem 10 may derive the distance d using speaker location techniques(which generally involves interfacing with the speakers 16 to cause themto emit tones by which the interactive system 10 may monitor using amicrophone to derive the location of each of the speakers 16).

In any event, the location determination module 44 may compute themiddle point between the two of the speakers 16 as the distance ddivided by two (d/2). In some instances, rather than configure thelocation determination module 44 with the distance d, the locationdetermination module 44 may be configured with the middle point, d/2.From this middle point d/2, the location determination module 44 maydetermine the starting point of a vector 60 that ends at the location53.

To compute the end of the vector 60, the location determination module44 may analyze the captured audio signals 51 received as at least aportion of the location information 49 to determine a ratio of theamplitude of the first ultrasound signal emitted by the speaker 16A (anddenoted as the ultrasound beam 17A in the example of FIG. 1) to theamplitude of the second ultrasound signal emitted by the speaker 16B(and denoted as the ultrasound beam 17B in the example of FIG. 1). Thelocation determination module 44 may then compute or otherwise determinethe location of the microphone relative to the speakers 16 based atleast on the determined ratio.

That is, using the ratio of the amplitude of the frequencies may enablethe location determine module 44 to determine an angle at which themicrophone 14 is relative to a center point equidistant between thespeakers 16 (which is another way of referring to the middle point,d/2). The location determination module 44 may compute the distance ofthe microphone 14 relative to the speakers 16 based on the amplitudesalone. This distance may be referred to as the length, l, of the vector60 in the example of FIG. 3. In some instances, the locationdetermination module 44 may compute the distance of the microphone 14relative to the speakers 16 based on the amplitudes alone. In effect,using the pair of speakers 16 enables the location determination module44 to form the vector 60 starting from the center point and ending atthe location of microphone, with the angle θ specified relative to theline 62 on which both of the speakers 16 reside.

In this sense, the above describes how the location determination module44 may compute this vector 60 from the center point between the speakers16, where the location determination module 40 uses the ratio of theamplitude of the frequencies compute the angle θ and uses the amplitudesto determine the length, l.

FIG. 4 is a diagram illustrating the computation of the location 53 byone of the user-operated device 30 or the interactive system 10 shown inthe examples of FIGS. 1 and 2 with respect to three speakers 16A-16C.That is, as described above, either the system 10 or the device 30 maycompute, based on the captured audio signals 51 or some derivativethereof, the location 53. While described below as being computed by thesystem 10, the computation aspects of the techniques may be performeddevice 30 or possibly some intervening device, such as a dongle devicethat interfaces with the interactive system 10 or the user-operateddevice 30.

As shown in the example of FIG. 4, the location determination module 44may compute the location 53 based on three vectors 70A-70C (“vectors70”). The location determination module 44 may determine each of thevectors 70 in the manner described above with respect to the example ofFIG. 3. That is, the location determination module 44 may be configuredwith the distance d between each of the various pairs of the speakers16, i.e., the speakers 16A and 16B, the speakers 16B and 16C and thespeakers 16A and 16C. To denote the different distances d, each of thedistances d contains a subscript with the two letters identifying eachpair, where the speaker 16A may be denoted as the “speaker A”, thespeaker 16B may be denoted as the “speaker B” and the speaker 16C may bedenoted as the “speaker C.” Accordingly, the distance d between thespeaker 16A and the speaker 16B may be denoted distance d_(AB), thedistance d between the speaker 16B and the speaker 16C may be denoteddistance d_(BC) and the distance d between the speaker 16A and thespeaker 16C may be denoted distance d_(AC). This same notation alsocarries over to the angles θ and the lengths, l, of each of the vectors70 and the locations 72A-72C (“locations 72”) to which each of thesevectors 70 identify.

In the example of FIG. 4, the inner circle denotes an approximatelocation of the microphone when the location is approximated with highconfidence. The outer circle denotes an approximate location of themicrophone when the location is approximated with low confidence. InFIG. 4, the three vectors 70 disagree with one another and do notidentify the corresponding locations 72 that agrees with one another.

In some instances, the techniques may enable a device to identify one ofthe vectors 70 that identifies the corresponding one of locations 72 ofthe microphone 14 outside of a threshold location derived based on theremaining two of the vectors 70. For example, in FIG. 4, a maximumvertical component of vector 70A (which may be denoted as the “vectorAB”) and the vector 72C (which may also be denoted as the “vector BC”)each locates the microphone 14 as being much closer to the speakers 16than the vertical component of vector 70C (which may also be denoted asthe “vector AC”). As a result, the location determination module 44 mayimplement this aspect of the techniques to define a maximum verticalthreshold of %110 percent as that of the vertical component of vector BCor AB. The device may then discard the identified one of the vectors 70that identifies a location of the microphone 14 outside of the thresholdlocation, which may result in discarding the vector 70C (or, per theother notation the vector AC). The location determination unit 44 maythen determine the location of the microphone 14 relative to thespeakers 16 based on the remaining two of the determined vectors 70,e.g., the remaining vectors AB and BC.

Alternatively, or in conjunction with the above aspect of the techniquesrelated to discarding various ones of the vectors 70, the techniques mayprovide for a voting system, whereby the location determination module44 clusters the three points or locations 72 identified by the threevectors 70 to find a “center of gravity” to be the location 53 of themicrophone 14, as shown in the example of FIG. 3. Moreover, in someinstances, the center of gravity aspect may be employed in a weightedfashion based on the amplitudes of the captured audio signals 51.

The aspects of the techniques described above to triangulate thelocation 53 of the microphone 14 can also be extended to accommodate anynumber of the speakers 16, where more of the speakers 16 may be used toidentify or otherwise determine the location 53 of the microphone 14 ina three dimensional space. Moreover, as shown in the example of FIG. 4,the speakers 16 may be arranged in an array configuration, wheresoftware manipulation of the audio signals 47 to be emitted by thespeakers 16 may be performed to form ultrasound beams in the mannerdescribed above using one or more of the speakers 15 in the array.

With respect to the speaker array, the techniques may be implementedsuch that a first frequency is supplied to each of the speakers 16 inthe form of the audio signals 47 in the speaker array, whereby all ofthe speakers 16 work coherently to direct the signal to one direction(e.g., the direction of speaker 16A shown in the example of FIG. 1). Ifa speaker array is used, the speaker array two or more speakers maycollectively work together to emit the ultrasound beam, where thelocation may be measured from the distance between these two or morespeakers (or if all of these speakers of the array are used, as thecenter of the speaker array). Moreover, the ultrasound beam formingmodule 42 may provide a second frequency different from the firstfrequency via the audio signals 47 concurrently with the above firstfrequency to each of the speakers 16 in the speaker array such that thissecond frequency is coherently directed to a second direction (such asthe direction of speaker 16B shown in the example of FIG. 1). In thismanner, the techniques described in this disclosure may enable a speakerarray to form ultrasonic beams that, when emitted by the speakers 16,may be directed in any direction in front of the speakers 16.

Speaker arrays may be employed in this manner to facilitatemanufacturing of the speakers 16 to accommodate the techniques describedin this disclosure. Rather than having the speakers 16 that rotateand/or turn by mechanical means, the speaker array may be designed suchthat all of the speakers 16 of the array face a single direction. Byusing the above described beam forming techniques to alter the signals47, the emitted ultrasound beam from the speakers 16 of the array may bedirected in different directions. Thus, signal processing may enable, asdescribed above, the sound or wavefront of the sound to be directed indifferent directions without having to manually adjust the speakers 16in the speaker array.

In this manner, the techniques may enable the location determinationmodule 44 to determining an amplitude of a third ultrasound signal (inaddition to the first and second ultrasound signals emitted by thespeakers 16) emitted by the speakers 16 and received by the microphone14. The location determination module 44 may then determine the vector70A from the speakers 16 to the microphone 14 based on the amplitude ofthe first ultrasound signal and the amplitude of the second ultrasoundsignal. The location determination module 44 may determine the vector70B based on the amplitude of the first ultrasound signal and theamplitude of the third ultrasound signal emitted by the speakers 16.Based on the amplitude of the second ultrasound signal and the amplitudeof the third ultrasound signal, the location determination module 44 mayalso determine the vector 70C. The location determination module 44 maydetermine the location of the microphone 14 relative to the speakers 16based on two or more of the determined vectors 70.

In some instances, the location determination module 44 may, as notedabove, identify one of the determined vectors 70 that identifies thecorresponding location 72 of the microphone 14 outside of a thresholdlocation derived based on the remaining two of the determined vectors70. The location determination module 44 may then discard the identifiedone of the determined vectors 70 that identifies the corresponding oneof locations 72 of the microphone 14 outside of the threshold location.The location determination module 44 may then determine the location 53of the microphone 14 relative to the speakers 16 based on the remainingtwo of the determined vectors 70.

While described above with respect to the two-dimensional location 53,the techniques of this disclosure may be extended to three-dimensionalspace when more speakers 16 are available. Given that measurement errormay exist in three-dimensional space, the location determination module44 may determine an average of the center location to which each of thevarious vectors 70 in this three-dimensional space point.

FIG. 5 is a flow chart illustrating exemplary operation of one of theinteractive system 10 or the user-operated device 30 (both of which areshown in the example of FIG. 2) in performing the techniques describedin this disclosure. As described above, either the system 10 or thedevice 30 may compute, based on the captured audio signals 51 or somederivative thereof, the location 53. While described below as beingcomputed by the system 10, the computation aspects of the techniques maybe performed device 30 or possibly some intervening device, such as adongle device that interfaces with the interactive system 10 or theuser-operated device 30.

In operation, the control unit 36 of the user-operated device 30 mayregister with the interactive system 10 (often automatically uponpowering on or activating the user-operated device 30 and assuming theinteractive system 10 is already powered on or activated) (80). Thecontrol unit 36 may register with the interactive system 10 by sending aregistration code or other registration information, whereupon theinteractive system 10 may begin generating the audio signals 47 (whennot already generating audio signals 47). The interactive system 10 mayregister the user-operated device 30 to operate in a location-basedinteractive manner with the interactive system 10 (82). The control unit32 may then invoke the ultrasound beam forming module 42 to generate theaudio signals 47 in the manner described above (84). The speakers 16 maythen output or play audio signals 47 to emit ultrasound beams, such asthe ultrasound beams 17 shown in the example of FIG. 1 (86).

The microphone 14 of the user-operated device 30 may sense, detect orotherwise capture the sound audio signals 47 (88), generating thecaptured audio signals 51 (which may differ from the audio signals 47due to noise or other interference) (88). The control unit 36 may theninvoke the microphone signal processing module 48 to process thecaptured audio signals 51 in the manner described above and therebygenerate the location information 49. That is, the microphone signalprocessing module 48 may generate the location information 49 based onthe captured audio signals 51 (90).

As noted above, the user-operated device 30 may register with theinteractive system 10. Part of this registration process may involveestablishing one or more communication channels 50 via a wired orwireless protocol, such as any of those described above. Theuser-operated device 30 may establish these communication channels 50 aspersistent channels that remain active as long as the user-operateddevice 30 and the interactive system 10 are operational. Alternatively,the user-operated device 30 may establish these communication channels50 for set durations or as required, such as in response to receivingthe location information 49. In any event, the interface 40 may transmitthe location information 49 via the communication channel 50 tointerface 34 of the interactive system 10 (92).

The interface 34, upon receiving this location information 49, maytransmit this location information 49 to the location determinationmodule 44. The location determination module 44 may then determine thelocation 53 in any of the various ways described above (94),transmitting this location 53 to the location-based processing module46. The location-based processing module 46 may then process thislocation 53 to perform any of the actions described in this disclosure(96).

FIG. 6 is a diagram illustrating an exemplary three-dimensional (3D)video data viewing system 98 in which various aspects of the techniquesdescribed in this disclosure may be performed. In the example of FIG. 6,a television 102 may include a speaker array 99 having four speakers16A-16D (“speakers 16”) that output ultrasound beams 100A-100D(“ultrasound beam 100”). The television 102 may in conjunction with thespeakers array 99 represent one example of the interactive system 10shown in the example of FIG. 2, and may be denoted for purposes ofreference as the “interactive system 10A.”

Additionally, shutter glasses 30A may represent one example of theuser-operated device 30 shown in the example of FIG. 2 and may bedenoted for purposes of reference as the “shutter glasses 30A.” Shutterglasses 30A may include the microphone 14 or an array of two or moremicrophones 14. The techniques may then be implemented in the mannerdescribed above to determine a location of the shutter glasses 30Arelative to the speaker array 99. Typically, in 3D video playback, thelocation, which is shown as location information 49A given thesimilarity or substantial similarity to location information 49 shown inthe example of FIG. 2 is utilized to determine a view that should bepresented to the user (not shown in the example of FIG. 6 for ease ofillustration purposes) wearing the shutter glasses 30A. This locationinformation 51A may be obtained in the manner described above using thetechniques described in this disclosure such that the interactive system10A may request a view of a scene that roughly corresponds to thelocation 53 of the shutter glasses 30A relative to the speaker array 99.

In this manner, the techniques may enable the television 102 to selectone of a number of views included within video data that approximatesviewing a scene presented by the video data from a relative locationsimilar to the determined location 53 of the microphone 14 relative tothe speakers 16 and present the selected one of the plurality of views.In this context, the techniques may provide an elegant, potentiallylow-power way by which to locate a potentially large number of viewersviewing a 3D display (such as the television 102) so as to facilitatepresenting what may be considered a “correct” view to each of theviewers wearing corresponding ones of the shutter glasses 30A. Whiledescribed above with respect to the active shutter glasses 30A, thetechniques may be performed with respect to passive types of the 3Dviewing glasses or any other type of 3D viewing glasses.

FIG. 7 is a flowchart illustrating exemplary operation of theinteractive system 10A and the shutter glasses 30A of FIG. 6 in performvarious aspects of the techniques described in this disclosure. Asdescribed above, either the system 10A or the device 30A may compute,based on the captured audio signals 51 or some derivative thereof, thelocation 53. While described below as being computed by the system 10A,the computation aspects of the techniques may be performed device 30A orpossibly some intervening device, such as a dongle device thatinterfaces with the interactive system 10A or the user-operated device30A.

In operation, the control unit 36 of the user-operated device 30A mayregister with the interactive system 10A (often automatically uponpowering on or activating the user-operated device 30A and assuming theinteractive system 10A is already powered on or activated) (110). Thecontrol unit 36 may register with the interactive system 10A by sendinga registration code or other registration information, whereupon theinteractive system 10A may begin generating the audio signals 47 (whennot already generating audio signals 47). The interactive system 10A mayregister the user-operated device 30A to operate in a location-basedinteractive manner with the interactive system 10A (112). The controlunit 32 may then invoke the ultrasound beam forming module 42 togenerate the audio signals 47 in the manner described above (114). Thespeakers 16 may then output or play audio signals 47 to emit ultrasoundbeams, such as the ultrasound beams 17 shown in the example of FIG. 1(116).

The microphone 14 of the user-operated device 30A may sense, detect orotherwise capture the sound audio signals 47 (118), generating thecaptured audio signals 51 (which may differ from the audio signals 47due to noise or other interference). The control unit 36 may then invokethe microphone signal processing module 48 to process the captured audiosignals 51 in the manner described above and thereby generate thelocation information 49A. That is, the microphone signal processingmodule 48 may generate the location information 49A based on thecaptured audio signals 51 (120). The interface 40 may transmit thelocation information 49A via the communication channel 50 to interface34 of the interactive system 10A (122).

The interface 34, upon receiving this location information 49A, maytransmit this location information 49A to the location determinationmodule 44. The location determination module 44 may then determine thelocation 53 in any of the various ways described above (124),transmitting this location 53 to the location-based processing module46. The location-based processing module 46 may then process thislocation 53 to perform any of the actions described in this disclosure.In the three dimensional viewing context, the location-based processingmodule 46 may process the determined location to select a view andpresent this view via the television 102 in the manner described above(126, 128).

FIG. 8 is a diagram illustrating an exemplary classroom system 140 thatmay perform various aspects of the techniques described in thisdisclosure. In the example of FIG. 8, a teacher computing device 142 mayinterface with a speaker array 99 having four speakers 16A-16D(“speakers 16”) that output ultrasound beams (which are not shown in theexample of FIG. 8, but which may be similar or substantially similar tothe ultrasound beams 100 shown in the example of FIG. 6). The teachercomputing device 142 may include one example of the interactive system10 shown in the example of FIG. 2, and may be denoted for purposes ofreference as the “interactive system 10B.” The interactive system 10Bmay differ slightly from the interactive system 10 shown in the exampleof FIG. 2 in that the interactive system 10B does not necessarilyinclude speakers 16 internal to the interactive system 10B.

Additionally, the classroom system 140 includes student-operated devices30B-30N, each of which may represent one example of the user-operateddevice 30 shown in the example of FIG. 2 and may collectively bereferred to, for purposes of reference, as the “student-operated devices30.” Each of student-operated devices 30 may include the microphone 14or an array of two or more microphones 14 (not shown in the example ofFIG. 8).

The techniques may be employed in the classroom system 140, where ateacher may utilize the teacher computing device 142, which mayrepresent a laptop computer, slate computer, smart phone or other typeof computing device, to identify students operating each of thestudent-operated devices 30. Each of the students may be associated withthe microphone 14 or microphone array 14 included within a correspondingone of the student-operated devices 30. The above techniques areperformed with respect to each of the microphones 14 so as to determinethe location of each of the microphones 14 relative to the speaker array14, which may be placed within the classroom and interfaced withwirelessly or physically coupled to the teacher computing device 142.

In the classroom system 140, each of the microphones 14 may be assigneda unique identifier, which in turn is associated with a student recordor profile. The profile may include a picture of the student, such thatthe interactive system 10B included within the teacher computing device142 may generate an image 144 that depicts the corresponding one of thedetermined locations 53B-53N specified within or derived from each ofthe respective location information 49B-49N sent by the student operateddevices 30 associated with students relative to one another and thespeaker array 99. This image may additionally specify studentinformation proximate to the location 53B-53N of each of the associatedstudents, such as the picture.

The computing device 142 may present the generated image 144 via adisplay 146 such that the teacher may view the student information. Thedisplay 146 may, as shown in the example of FIG. 8, be included withinthe teacher computing device 142 or external from the teacher computingdevice 142. The display 146 may comprise a liquid crystal display (LCD),a plasma display, a cathode ray tube (CRT) display, an organic lightemitting diode (OLED) display, a light emitting diode (LED) display orany other type of display or visual interface. This student information,in addition to specifying a picture, may also include one or more of aname of the corresponding student, an age of the corresponding student,a gender of the corresponding student, a medical condition of thecorresponding student, an allergy of the corresponding student, aranking of the corresponding student and a grade of the correspondingstudent. In this context, the techniques may facilitate interactionswith the students, especially at the beginning of the school year as theteacher learns the particulars of each student.

FIG. 9 is a flowchart illustrating exemplary operation of the classroomsystem 140 of FIG. 8 in performing various aspects of the techniquesdescribed in this disclosure. As described above, either the system 10Bor the devices 30 shown in the example of FIG. 8 may compute, based onthe captured audio signals 51 or some derivative thereof, the location53. While described below as being computed by the system 10B, thecomputation aspects of the techniques may be performed devices 30 orpossibly some intervening device, such as a dongle device thatinterfaces with the interactive system 10B or the student-operateddevices 30. Moreover, while described with respect to student-operateddevice 30B, the techniques may be performed by any one ofstudent-operated devices 30B-30N to perform the operations attributed tostudent-operated device 30B below.

In operation, the control unit 36 of the student-operated device 30Bmay, for example, register with the interactive system 10B (oftenautomatically upon powering on or activating the student-operated device30B and assuming the interactive system 10B is already powered on oractivated) (150). The control unit 36 may register with the interactivesystem 10B by sending a registration code or other registrationinformation, whereupon the interactive system 10B may begin generatingthe audio signals 47 (when not already generating audio signals 47). Theinteractive system 10B may register the student-operated device 30B tooperate in a location-based interactive manner with the interactivesystem 10B (152). The control unit 32 may then invoke the ultrasoundbeam forming module 42 to generate the audio signals 47 in the mannerdescribed above (154). The speakers 16 may then output or play audiosignals 47 to emit ultrasound beams, such as the ultrasound beams 17shown in the example of FIG. 1 (156).

The microphone 14 of the student-operated device 30B may sense, detector otherwise capture the sound audio signals 47 (158), generating thecaptured audio signals 51 (which may differ from the audio signals 47due to noise or other interference). The control unit 36 may then invokethe microphone signal processing module 48 to process the captured audiosignals 51 in the manner described above and thereby generate thelocation information 49B. That is, the microphone signal processingmodule 48 may generate the location information 49B based on thecaptured audio signals 51 (160). The interface 40 may transmit thelocation information 49B via the communication channel 50 to interface34 of the interactive system 10B (162).

The interface 34, upon receiving this location information 49B, maytransmit this location information 49B to the location determinationmodule 44. The location determination module 44 may then determine thelocation 53 in any of the various ways described above (164),transmitting this location 53 to the location-based processing module46. The location-based processing module 46 may then process thislocation 53 to perform any of the actions described in this disclosure.In the classroom context, the location-based processing module 46 maydetermine a student associated with the student-operated device 30Bbased on the location information 53 (166). The location-basedprocessing module 46 may then retrieve student information associatedwith the determined student (168). The location-based processing module46 may generate an image based on the determined location and theretrieved student information and display the image via the display 146,as described above (170, 172).

FIG. 10 is a diagram illustrating an exemplary airline system 200 thatmay perform various aspects of the techniques described in thisdisclosure. In the example of FIG. 10, an airline computing device 202may interface with speaker arrays 99P-99Z (“speaker arrays 99”) havingspeakers that output ultrasound beams (which are not shown in theexample of FIG. 10, but which may be similar or substantially similar tothe ultrasound beams 100 shown in the example of FIG. 6). The airlinecomputing device 202 may include one example of the interactive system10 shown in the example of FIG. 2, and may be denoted for purposes ofreference as the “interactive system 10C.” The interactive system 10Cmay differ slightly from the interactive system 10 shown in the exampleof FIG. 2 in that the interactive system 10C does not necessarilyinclude speaker arrays 99 internal to the interactive system 10B.

Additionally, the airline system 200 includes passenger-operated devices30P-30Z, each of which may represent one example of the user-operateddevice 30 shown in the example of FIG. 2 and may collectively bereferred to, for purposes of reference, as the “passenger-operateddevices 30.” Each of student-operated devices 30 may include themicrophone 14 or an array of two or more microphones 14 (not shown inthe example of FIG. 10).

The techniques may be performed in the context of the airline system200, which may represent one example of a transit registration system.In other words, the airline system 200 may be utilized for transit andother applications. To illustrate, consider airline passengers that areassigned a seat. The airline may utilize the airline system 200 todetermine when all passengers have taken their seats. Moreover, theairline system 200 may interface with displays 204P-204Z (“displays204,” which may be similar or substantially similar to display 146 ofthe example of FIG. 8) on the backs of seats, presenting a correspondingone of images 206P-206Z (“images 206”) to the passengers based on thedetermination that the passenger has a determined location 53 proximateto their assigned seat. The determined location 53 may be includedwithin or otherwise derived from location information 49P-49Z (which maybe similar or substantially similar to the location information 49described above with respect to FIG. 2).

In other words, each passenger or customer of the airline may receive amicrophone 14 in the form of a corresponding one of thepassenger-operated devices 30 upon boarding the plane or may utilize anexisting microphone 14 present in their own personal devices, e.g., asmart phone, laptop computer, slate computer, etc. The speaker arrays 99may be placed with respect to a seat to which the different customersare able to sit. That is, the speaker arrays 99 may be located on theback of the seat in front of the seat in which the different customersare assigned.

In this example, the ultrasound mesh localization techniques may beperformed with respect to each of the microphones present or includedwithin the speaker arrays 99 so as to determine the location 53 of eachof the passenger-operated devices 30 relative to the speaker arrays 99.Based on the determined location 53 of each of the passenger-operateddevices 30, the on-board airline computing system 202 may determine thatthe different customers have sat in the seat, whereupon the on-boardairline computing system 202 may present one of images 206 via acorresponding one of displays 204 (often located in seatback of the seatin front of the customer) in response to determining that the differentcustomers have sat in the seat.

To provide a few examples, the images 206 may each specify one or moreof a personalized greeting, personalized travel information tailored toaccommodate profiles of the different customers, a travel upgradeavailable to the different customers, frequent flyer mile statusspecific to the different customers, registration information,connecting flight information specific to travel itineraries of thedifferent customers, car rental information specific to the differentcustomers, and a customs form. In this context, the techniques mayfacilitate greeting of the customer, providing various informationrelevant to the customers itinerary.

While described above with respect to being performed in an airlinesetting, the techniques may be performed in the context of any transitsetting. That is, the interactive system 10C may be employed in subways,busses, or any other setting having passengers that board a mode oftransportation. Accordingly, the techniques should not be limited inthis respect.

FIG. 11 is a flowchart illustrating exemplary operation of the airlinesystem 200 of FIG. 10 in performing various aspects of the techniquesdescribed in this disclosure. As described above, either the system 10Cor the devices 30 shown in the example of FIG. 11 may compute, based onthe captured audio signals 51 or some derivative thereof, the location53. While described below as being computed by the system 10C, thecomputation aspects of the techniques may be performed devices 30 orpossibly some intervening device, such as a dongle device thatinterfaces with the interactive system 10C or the passenger-operateddevices 30. Moreover, while described with respect to student-operateddevice 30P, the techniques may be performed by any one ofpassenger-operated devices 30P-30Z to perform the operations attributedto student-operated device 30B below.

In operation, the control unit 36 of the passenger-operated device 30Pmay, for example, register with the interactive system 10C (oftenautomatically upon powering on or activating the passenger-operateddevice 30P and assuming the interactive system 10C is already powered onor activated) (220). The control unit 36 may register with theinteractive system 10C by sending a registration code or otherregistration information, whereupon the interactive system 10C may begingenerating the audio signals 47 (when not already generating audiosignals 47). The interactive system 10C may register thepassenger-operated device 30P to operate in a location-based interactivemanner with the interactive system 10C (222). The control unit 32 maythen invoke the ultrasound beam forming module 42 to generate the audiosignals 47 in the manner described above (224). The speakers 16 may thenoutput or play audio signals 47 to emit ultrasound beams, such as theultrasound beams 17 shown in the example of FIG. 1 (226).

The microphone 14 of the passenger-operated device 30P may sense, detector otherwise capture the sound audio signals 47 (228), generating thecaptured audio signals 51 (which may differ from the audio signals 47due to noise or other interference). The control unit 36 may then invokethe microphone signal processing module 48 to process the captured audiosignals 51 in the manner described above and thereby generate thelocation information 49P. That is, the microphone signal processingmodule 48 may generate the location information 49P based on thecaptured audio signals 51 (230). The interface 40 may transmit thelocation information 49P via the communication channel 50 to interface34 of the interactive system 10C (232).

The interface 34, upon receiving this location information 49P, maytransmit this location information 49P to the location determinationmodule 44. The location determination module 44 may then determine thelocation 53 in any of the various ways described above (234),transmitting this location 53 to the location-based processing module46. The location-based processing module 46 may then process thislocation 53 to perform any of the actions described in this disclosure.In this transit context, the location-based processing module 46 maydetermine a passenger associated with the passenger-operated device 30Pbased on the location information 53 (236). The location-basedprocessing module 46 may then retrieve passenger information associatedwith the determined passenger (238). The location-based processingmodule 46 may generate an image based on the determined location and theretrieved passenger information (239). The location-based processingmodule 46 may then select one of the displays 204 associated with thepassenger based on the passenger information (which may specify a seatto which the passenger is to sit) (240). The location-based processingmodule 46 may then display the image via the selected one of thedisplays 204, i.e., display 204P in this example (242).

While various contexts or systems are described above, the techniquesmay be performed in a wide variety of contexts or systems. For example,the techniques may be performed in a gaming context, with a microphoneenabled controller in hand or worn. The user may then move around theroom, and the gaming console may include the interactive system tolocate each of the users (assuming the controller provides anothercommunication channel to report its location to the main system).

As another example, the techniques may be performed in the context of amedia playback. That is, when using our handsets and tablet speakers assatellite speakers for a surround sound system, the current interactivesystem may be used to locate each satellite device and dispatch signalsbased on the located devices.

As another example, the techniques may be performed in the conferencingcontext. To illustrate, in a conference room, each attendee may wear abadge with microphone (which may comprise the user-operated device). Theinteractive system may then be able to detect a location of each onerelative to the table. The interactive system may then interface with amicrophone array on the table to form different beams toward each userand specifically pickup their words and tag the contents with theiridentification or other information.

As yet another example, the techniques may be performed in theperforming arts context. To illustrate, the “spot person” may bereplaced with the interactive system, which interfaces with thespotlight to automatically follow a microphone worn by the performeronce the location of the performer is identified using the interactivesystem.

As still yet another example, the techniques may be performed in thecontext of road safety. The interactive system may be installed in a carscanning a driver wearing a small device with microphone. Whenever thehead of the driver turns to the side there is a potential for an impactin the front. The head motion can be reported to the interactive system,and the interactive system may issue a warning sound to alert the driverof the potential for impact.

It should be understood that, depending on the example, certain acts orevents of any of the methods described herein can be performed in adifferent sequence, may be added, merged, or left out altogether (e.g.,not all described acts or events are necessary for the practice of themethod). Moreover, in certain examples, acts or events may be performedconcurrently, e.g., through multi-threaded processing, interruptprocessing, or multiple processors, rather than sequentially. Inaddition, while certain aspects of this disclosure are described asbeing performed by a single module or unit for purposes of clarity, itshould be understood that the techniques of this disclosure may beperformed by a combination of units or modules associated with a videocoder.

In one or more examples, the functions described may be implemented inhardware, software, firmware, or any combination thereof. If implementedin software, the functions may be stored on or transmitted over as oneor more instructions or code on a computer-readable medium and executedby a hardware-based processing unit. Computer-readable media may includecomputer-readable storage media, which corresponds to a tangible mediumsuch as data storage media, or communication media including any mediumthat facilitates transfer of a computer program from one place toanother, e.g., according to a communication protocol.

In this manner, computer-readable media generally may correspond to (1)tangible computer-readable storage media which is non-transitory or (2)a communication medium such as a signal or carrier wave. Data storagemedia may be any available media that can be accessed by one or morecomputers or one or more processors to retrieve instructions, codeand/or data structures for implementation of the techniques described inthis disclosure. A computer program product may include acomputer-readable medium.

By way of example, and not limitation, such computer-readable storagemedia can comprise RAM, ROM, EEPROM, CD-ROM or other optical diskstorage, magnetic disk storage, or other magnetic storage devices, flashmemory, or any other medium that can be used to store desired programcode in the form of instructions or data structures and that can beaccessed by a computer. Also, any connection is properly termed acomputer-readable medium. For example, if instructions are transmittedfrom a website, server, or other remote source using a coaxial cable,fiber optic cable, twisted pair, digital subscriber line (DSL), orwireless technologies such as infrared, radio, and microwave, then thecoaxial cable, fiber optic cable, twisted pair, DSL, or wirelesstechnologies such as infrared, radio, and microwave are included in thedefinition of medium.

It should be understood, however, that computer-readable storage mediaand data storage media do not include connections, carrier waves,signals, or other transient media, but are instead directed tonon-transient, tangible storage media. Disk and disc, as used herein,includes compact disc (CD), laser disc, optical disc, digital versatiledisc (DVD), floppy disk and blu-ray disc where disks usually reproducedata magnetically, while discs reproduce data optically with lasers.Combinations of the above should also be included within the scope ofcomputer-readable media.

Instructions may be executed by one or more processors, such as one ormore digital signal processors (DSPs), general purpose microprocessors,application specific integrated circuits (ASICs), field programmablelogic arrays (FPGAs), or other equivalent integrated or discrete logiccircuitry. Accordingly, the term “processor,” as used herein may referto any of the foregoing structure or any other structure suitable forimplementation of the techniques described herein. In addition, in someaspects, the functionality described herein may be provided withindedicated hardware and/or software modules configured for encoding anddecoding, or incorporated in a combined codec. Also, the techniquescould be fully implemented in one or more circuits or logic elements.

The techniques of this disclosure may be implemented in a wide varietyof devices or apparatuses, including a wireless handset, an integratedcircuit (IC) or a set of ICs (e.g., a chip set). Various components,modules, or units are described in this disclosure to emphasizefunctional aspects of devices configured to perform the disclosedtechniques, but do not necessarily require realization by differenthardware units. Rather, as described above, various units may becombined in a codec hardware unit or provided by a collection ofinteroperative hardware units, including one or more processors asdescribed above, in conjunction with suitable software and/or firmware.

Various embodiments of the invention have been described. These andother embodiments are within the scope of the following claims.

What is claimed is:
 1. A method comprising: determining an amplitude ofa first ultrasound signal emitted by one or more transducers andreceived by a microphone, wherein the first ultrasound signal is of afirst frequency; determining an amplitude of a second ultrasound signalemitted by the one or more transducers and received by the microphone,wherein the second ultrasound signal is of a second frequency differentfrom the first frequency; and determining a location of the microphonerelative to the one or more transducers based at least on the determinedamplitude of the first ultrasound signal and the determined amplitude ofthe second ultrasound signal.
 2. The method of claim 1, whereindetermining a location of the microphone relative to the one or moretransducers comprises: determining a ratio of the amplitude of the firstultrasound signal to the amplitude of the second ultrasound signal; anddetermining the location of the microphone relative to the one or moretransducers based at least on the determined ratio.
 3. The method ofclaim 1, further comprising determining an amplitude of a thirdultrasound signal emitted by the one or more transducers and received bythe microphone, wherein determining the location of the microphonerelative to the one or more transducers comprises: based on theamplitude of the first ultrasound signal and the amplitude of the secondultrasound signal, determining a first vector from the one or moretransducers to the microphone; based on the amplitude of the firstultrasound signal and the amplitude of the third ultrasound signal,determining a second vector from the one or more transducers to themicrophone; based on the amplitude of the second ultrasound signal andthe amplitude of the third ultrasound signal, determining a third vectorfrom the one or more transducers of the microphone; and determining thelocation of the microphone relative to the one or more transducers basedon two or more of the determined first vector, the determined secondvector and the determined third vector.
 4. The method of claim 3,wherein determining the location of the microphone relative to the oneor more transducers comprises: identifying one of the determined firstvector, the determined second vector and the determined third vectorthat identifies a location of the microphone outside of a thresholdlocation derived based on the remaining two of the determined firstvector, the determined second vector and the determined third vector;discarding the identified one of the determined first vector, thedetermined second vector and the determined third vector that identifiesa location of the microphone outside of the threshold location; anddetermining the location of the microphone relative to the one or moretransducers based on the remaining two of the determined first vector,the determined second vector and the determined third vector.
 5. Themethod of claim 1, wherein the one or more transducers are included in afirst device, wherein the microphone is included in a second device,wherein determining the amplitude of the first ultrasound signalcomprises receiving, with the first device, the amplitude of the firstultrasound signal from the second device, wherein determining theamplitude of the second ultrasound signal comprises receiving, with thefirst device, the amplitude of the second ultrasound signal from thesecond device, and wherein determining the location of the microphonecomprises determining, with the first device, the location of themicrophone relative to the one or more transducers based at least on thedetermined amplitude of the first ultrasound signal and the determinedamplitude of the second ultrasound signal.
 6. The method of claim 1,wherein the one or more transducers are included in a first device,wherein the microphone is included in a second device, whereindetermining the amplitude of the first ultrasound signal comprisesdetermining, with the second device, the amplitude of the firstultrasound signal, wherein determining the amplitude of the secondultrasound signal comprises determining, with the second device, theamplitude of the second ultrasound signal, and wherein determining thelocation of the microphone comprises determining, with the seconddevice, the location of the microphone relative to the one or moretransducers based at least on the determined amplitude of the firstultrasound signal and the determined amplitude of the second ultrasoundsignal.
 7. The method of claim 1, wherein the transducers are arrangedas an array of transducers.
 8. The method of claim 7, wherein the arrayof transducers are arranged such that each of the transducers in thearray face the same direction, wherein the method further comprises:processing the first ultrasound signal prior to providing the firstultrasound signal to the transducers in the array so as to generate afirst directional ultrasound signal that, when emitted by thetransducers in the array, appears to be directed in a first direction;processing the second ultrasound signal prior to providing the secondultrasound signal to the transducers in the array so as to generate asecond directional ultrasound signal that, when emitted by thetransducers in the array, appears to be directed in a second direction;and concurrently providing the first and second directional ultrasoundsignals to the transducers in the array such that the transducers in thearray concurrently emit the first and second direction ultrasoundsignals as the first and second ultrasound signals.
 9. The method ofclaim 1, wherein the microphone is included within or adjacent tothree-dimensional viewing glasses, wherein the one or more transducersare included within or adjacent to a three dimensional display device,and wherein the method further comprises: selecting one of a pluralityof views included within video data that approximates viewing a scenepresented by the video data from a relative location similar to thatdetermined location of the microphone relative to the one or moretransducers; and presenting the selected one of the plurality of views.10. The method of claim 1, wherein the microphone comprises one of aplurality of microphones, each of which is associated with a differentstudent; wherein the method is performed with respect to each of theplurality of microphones so as to determine the location of each of theplurality of microphones relative to the one or more transducers,wherein the method further comprises: generating an image that depictsthe determined location of each of the microphones as the location ofthe associated students relative to one another and the one or moretransducers and that specifies student information proximate to thelocation of each of the associated students; and presenting thegenerated image.
 11. The method of claim 10, wherein the studentinformation comprises one or more of a name of the correspondingstudent, an age of the corresponding student, a gender of thecorresponding student, a medical condition of the corresponding student,an allergy of the corresponding student, a ranking of the correspondingstudent and a grade of the corresponding student.
 12. The method ofclaim 1, wherein the microphone comprises one of a plurality ofmicrophones, each of which is associated with a different customer,wherein the one or more transducers comprise two or more transducersplaced with respect to a seat in which the different customers are ableto sit, wherein the method is performed with respect to each of theplurality of microphones so as to determine the location of each of theplurality of microphones relative to the one or more transducers, andwherein the method further comprises: determining that the differentcustomers have sat in the seat based on the determined location of eachof the plurality of microphones; and presenting an image via a displayin response to determining that the different customers have sat in theseat.
 13. The method of claim 12, wherein the image includes one or moreof a personalized greeting, personalized travel information tailored toaccommodate profiles of the different customers, a travel upgradeavailable to the different customers, frequent flyer mile statusspecific to the different customers, registration information,connecting flight information specific to travel itineraries of thedifferent customers, car rental information specific to the differentcustomers, and a customs form.
 14. An interactive system comprising: oneor more processors configured to determine an amplitude of a firstultrasound signal emitted by one or more transducers and received by amicrophone, wherein the first ultrasound signal is of a first frequency,determine an amplitude of a second ultrasound signal emitted by the oneor more transducers and received by the microphone, wherein the secondultrasound signal is of a second frequency different from the firstfrequency, and determine a location of the microphone relative to theone or more transducers based at least on the determined amplitude ofthe first ultrasound signal and the determined amplitude of the secondultrasound signal.
 15. The interactive system of claim 14, wherein theone or more processors are further configured to, when determining alocation of the microphone relative to the one or more transducers,determine a ratio of the amplitude of the first ultrasound signal to theamplitude of the second ultrasound signal, and determine the location ofthe microphone relative to the one or more transducers based at least onthe determined ratio.
 16. The interactive system of claim 14, whereinthe one or more processors are further configured to determine anamplitude of a third ultrasound signal emitted by the one or moretransducers and received by the microphone, wherein the one or moreprocessors are further configured to, when determining the location ofthe microphone relative to the one or more transducers, based on theamplitude of the first ultrasound signal and the amplitude of the secondultrasound signal, determine a first vector from the one or moretransducers to the microphone, based on the amplitude of the firstultrasound signal and the amplitude of the third ultrasound signal,determine a second vector from the one or more transducers to themicrophone, based on the amplitude of the second ultrasound signal andthe amplitude of the third ultrasound signal, determine a third vectorfrom the one or more transducers of the microphone, and determine thelocation of the microphone relative to the one or more transducers basedon two or more of the determined first vector, the determined secondvector and the determined third vector.
 17. The interactive system ofclaim 16, wherein the one or more processors are further configured to,when determining the location of the microphone relative to the one ormore transducers, identify one of the determined first vector, thedetermined second vector and the determined third vector that identifiesa location of the microphone outside of a threshold location derivedbased on the remaining two of the determined first vector, thedetermined second vector and the determined third vector, discard theidentified one of the determined first vector, the determined secondvector and the determined third vector that identifies a location of themicrophone outside of the threshold location, and determine the locationof the microphone relative to the one or more transducers based on theremaining two of the determined first vector, the determined secondvector and the determined third vector.
 18. The interactive system ofclaim 14, wherein the one or more transducers are included in a firstdevice of the interactive system, wherein the microphone is included ina second device that interfaces with the interactive system, wherein theone or more processors are further configured to, when determining theamplitude of the first ultrasound signal, receive the amplitude of thefirst ultrasound signal from the second device, wherein the one or moreprocessors are further configured to, when determining the amplitude ofthe second ultrasound signal, receive the amplitude of the secondultrasound signal from the second device, and wherein the one or moreprocessors are further configured to, when determining the location ofthe microphone, determine the location of the microphone relative to theone or more transducers based at least on the determined amplitude ofthe first ultrasound signal and the determined amplitude of the secondultrasound signal.
 19. The interactive system of claim 14, wherein theone or more transducers are included in a first device of theinteractive system, wherein the microphone is included in a seconddevice that interfaces with the interactive system, wherein the seconddevice determines the amplitude of the first ultrasound signal,determines the amplitude of the second ultrasound signal, and determinesthe location of the microphone relative to the one or more transducersbased at least on the determined amplitude of the first ultrasoundsignal and the determined amplitude of the second ultrasound signal,wherein the one or more processors are further configured to, whendetermining the location of the microphone, receive the location of themicrophone relative to the one or more transducers from the seconddevice.
 20. The interactive system of claim 14, wherein the transducersare arranged as an array of transducers.
 21. The interactive system ofclaim 20, wherein the array of transducers are arranged such that eachof the transducers in the array face the same direction, wherein the oneor more processors are further configured to process the firstultrasound signal prior to providing the first ultrasound signal to thetransducers in the array so as to generate a first directionalultrasound signal that, when emitted by the transducers in the array,appears to be directed in a first direction, process the secondultrasound signal prior to providing the second ultrasound signal to thetransducers in the array so as to generate a second directionalultrasound signal that, when emitted by the transducers in the array,appears to be directed in a second direction, and concurrently providethe first and second directional ultrasound signals to the transducersin the array such that the transducers in the array concurrently emitthe first and second direction ultrasound signals as the first andsecond ultrasound signals.
 22. The interactive system of claim 14,wherein the microphone is included within or adjacent tothree-dimensional viewing glasses, wherein the interactive system isincluded within a three dimensional display device, wherein the one ormore transducers are included within or adjacent to the threedimensional display device, and wherein the one or more processors arefurther configured to select one of a plurality of views included withinvideo data that approximates viewing a scene presented by the video datafrom a relative location similar to that determined location of themicrophone relative to the one or more transducers, and present theselected one of the plurality of views.
 23. The interactive system ofclaim 14, wherein the microphone comprises one of a plurality ofmicrophones, each of which is associated with a different student, andwherein the one or more processors are further configured to determinethe location of the plurality of microphones relative to the one or moretransducers, generate an image that depicts the determined location ofeach of the microphones as the location of the associated studentsrelative to one another and the one or more transducers and thatspecifies student information proximate to the location of each of theassociated students, and present the generated image.
 24. Theinteractive system of claim 23, wherein the student informationcomprises one or more of a name of the corresponding student, an age ofthe corresponding student, a gender of the corresponding student, amedical condition of the corresponding student, an allergy of thecorresponding student, a ranking of the corresponding student and agrade of the corresponding student.
 25. The interactive system of claim14, wherein the microphone comprises one of a plurality of microphones,each of which is associated with a different customer, wherein the oneor more transducers comprise two or more transducers placed with respectto a seat in which the different customers are able to sit, wherein theone or more processors are further configured to determine a location ofthe plurality of microphones so relative to the one or more transducers,determine that the different customers have sat in the seat based on thedetermined location of each of the plurality of microphones, and presentan image via a display in response to determining that the differentcustomers have sat in the seat.
 26. The interactive system of claim 25,wherein the image includes one or more of a personalized greeting,personalized travel information tailored to accommodate profiles of thedifferent customers, a travel upgrade available to the differentcustomers, frequent flyer mile status specific to the differentcustomers, registration information, connecting flight informationspecific to travel itineraries of the different customers, car rentalinformation specific to the different customers, and a customs form. 27.An interactive system comprising: means for determining an amplitude ofa first ultrasound signal emitted by one or more transducers andreceived by a microphone, wherein the first ultrasound signal is of afirst frequency; means for determining an amplitude of a secondultrasound signal emitted by the one or more transducers and received bythe microphone, wherein the second ultrasound signal is of a secondfrequency different from the first frequency; and means for determininga location of the microphone relative to the one or more transducersbased at least on the determined amplitude of the first ultrasoundsignal and the determined amplitude of the second ultrasound signal. 28.The interactive system of claim 27, wherein the means for determining alocation of the microphone relative to the one or more transducerscomprises: means for determining a ratio of the amplitude of the firstultrasound signal to the amplitude of the second ultrasound signal; andmeans for determining the location of the microphone relative to the oneor more transducers based at least on the determined ratio.
 29. Theinteractive system of claim 27, further comprising means for determiningan amplitude of a third ultrasound signal emitted by the one or moretransducers and received by the microphone, wherein the means fordetermining the location of the microphone relative to the one or moretransducers comprises: means for, based on the amplitude of the firstultrasound signal and the amplitude of the second ultrasound signal,determining a first vector from the one or more transducers to themicrophone; means for, based on the amplitude of the first ultrasoundsignal and the amplitude of the third ultrasound signal, determining asecond vector from the one or more transducers to the microphone; meansfor, based on the amplitude of the second ultrasound signal and theamplitude of the third ultrasound signal, determining a third vectorfrom the one or more transducers of the microphone; and means fordetermining the location of the microphone relative to the one or moretransducers based on two or more of the determined first vector, thedetermined second vector and the determined third vector.
 30. Theinteractive system of claim 29, wherein the means for determining thelocation of the microphone relative to the one or more transducerscomprises: means for identifying one of the determined first vector, thedetermined second vector and the determined third vector that identifiesa location of the microphone outside of a threshold location derivedbased on the remaining two of the determined first vector, thedetermined second vector and the determined third vector; means fordiscarding the identified one of the determined first vector, thedetermined second vector and the determined third vector that identifiesa location of the microphone outside of the threshold location; andmeans for determining the location of the microphone relative to the oneor more transducers based on the remaining two of the determined firstvector, the determined second vector and the determined third vector.31. The interactive system of claim 27, wherein the interactive systemis included in a first device, wherein the microphone is included in asecond device that interfaces with the interactive system, wherein themeans for determining the amplitude of the first ultrasound signalcomprises means for receiving the amplitude of the first ultrasoundsignal from the second device, wherein the means for determining theamplitude of the second ultrasound signal comprises means for receivingthe amplitude of the second ultrasound signal from the second device,and wherein the means for determining the location of the microphonecomprises means for determining the location of the microphone relativeto the one or more transducers based at least on the determinedamplitude of the first ultrasound signal and the determined amplitude ofthe second ultrasound signal.
 32. The interactive system of claim 27,wherein the interactive system is included in a first device, whereinthe microphone is included in a second device, wherein the second devicedetermines the amplitude of the first ultrasound signal, determines theamplitude of the second ultrasound signal, and determines the locationof the microphone relative to the one or more transducers based at leaston the determined amplitude of the first ultrasound signal and thedetermined amplitude of the second ultrasound signal, wherein the meansfor determining the location of the microphone comprises means forreceive the location of the microphone relative to the one or moretransducers from the second device.
 33. The interactive system of claim27, wherein the transducers are arranged as an array of transducers. 34.The interactive system of claim 33, wherein the array of transducers arearranged such that each of the transducers in the array face the samedirection, wherein the interactive system further comprises: means forprocessing the first ultrasound signal prior to providing the firstultrasound signal to the transducers in the array so as to generate afirst directional ultrasound signal that, when emitted by thetransducers in the array, appears to be directed in a first direction;means for processing the second ultrasound signal prior to providing thesecond ultrasound signal to the transducers in the array so as togenerate a second directional ultrasound signal that, when emitted bythe transducers in the array, appears to be directed in a seconddirection; and means for concurrently providing the first and seconddirectional ultrasound signals to the transducers in the array such thatthe transducers in the array concurrently emit the first and seconddirection ultrasound signals as the first and second ultrasound signals.35. The interactive system of claim 27, wherein the microphone isincluded within or adjacent to three-dimensional viewing glasses,wherein the interactive system is included in a three dimensionaldisplay device, wherein the one or more transducers are included withinor adjacent to the three dimensional display device, and wherein theinteractive system further comprises: means for selecting one of aplurality of views included within video data that approximates viewinga scene presented by the video data from a relative location similar tothat determined location of the microphone relative to the one or moretransducers, and means for presenting the selected one of the pluralityof views.
 36. The interactive system of claim 27, wherein the microphonecomprises one of a plurality of microphones, each of which is associatedwith a different student; wherein the means for determining the locationcomprises means for determining the location of each of the plurality ofmicrophones relative to the one or more transducers, wherein theinteractive system further comprises: means for generating an image thatdepicts the determined location of each of the microphones as thelocation of the associated students relative to one another and the oneor more transducers and that specifies student information proximate tothe location of each of the associated students; and means forpresenting the generated image.
 37. The interactive system of claim 36,wherein the student information comprises one or more of a name of thecorresponding student, an age of the corresponding student, a gender ofthe corresponding student, a medical condition of the correspondingstudent, an allergy of the corresponding student, a ranking of thecorresponding student and a grade of the corresponding student.
 38. Theinteractive system of claim 27, wherein the microphone comprises one ofa plurality of microphones, each of which is associated with a differentcustomer, wherein the one or more transducers comprise two or moretransducers placed with respect to a seat in which the differentcustomers are able to sit, wherein the means for determining thelocation comprises means for determining the location of each of theplurality of microphones relative to the one or more transducers, andwherein the interactive system further comprises: means for determiningthat the different customers have sat in the seat based on thedetermined location of each of the plurality of microphones; and meansfor presenting an image via a display in response to determining thatthe different customers have sat in the seat.
 39. The interactive systemof claim 38, wherein the image includes one or more of a personalizedgreeting, personalized travel information tailored to accommodateprofiles of the different customers, a travel upgrade available to thedifferent customers, frequent flyer mile status specific to thedifferent customers, registration information, connecting flightinformation specific to travel itineraries of the different customers,car rental information specific to the different customers, and acustoms form.
 40. A non-transitory computer-readable storage mediumhaving stored thereon instructions that, when executed, cause one ormore processors of an interactive system to: determine an amplitude of afirst ultrasound signal emitted by one or more transducers and receivedby a microphone, wherein the first ultrasound signal is of a firstfrequency; determine an amplitude of a second ultrasound signal emittedby the one or more transducers and received by the microphone, whereinthe second ultrasound signal is of a second frequency different from thefirst frequency; and determine a location of the microphone relative tothe one or more transducers based at least on the determined amplitudeof the first ultrasound signal and the determined amplitude of thesecond ultrasound signal.
 41. The non-transitory computer-readablestorage medium of claim 40, wherein the instructions further cause, whenexecuted, the one or more processors to, when determining a location ofthe microphone relative to the one or more transducers, determine aratio of the amplitude of the first ultrasound signal to the amplitudeof the second ultrasound signal, and determine the location of themicrophone relative to the one or more transducers based at least on thedetermined ratio.
 42. The non-transitory computer-readable storagemedium of claim 40, further comprising instructions that, when executedcause the one or more processors to determine an amplitude of a thirdultrasound signal emitted by the one or more transducers and received bythe microphone, wherein the instructions further cause, when executed,the one or more processors to, when determining the location of themicrophone relative to the one or more transducers, based on theamplitude of the first ultrasound signal and the amplitude of the secondultrasound signal, determine a first vector from the one or moretransducers to the microphone, based on the amplitude of the firstultrasound signal and the amplitude of the third ultrasound signal,determine a second vector from the one or more transducers to themicrophone, based on the amplitude of the second ultrasound signal andthe amplitude of the third ultrasound signal, determine a third vectorfrom the one or more transducers of the microphone, and determine thelocation of the microphone relative to the one or more transducers basedon two or more of the determined first vector, the determined secondvector and the determined third vector.
 43. The non-transitorycomputer-readable storage medium of claim 42, wherein the instructionsfurther cause, when executed, the one or more processors to, whendetermining the location of the microphone relative to the one or moretransducers, identify one of the determined first vector, the determinedsecond vector and the determined third vector that identifies a locationof the microphone outside of a threshold location derived based on theremaining two of the determined first vector, the determined secondvector and the determined third vector, discard the identified one ofthe determined first vector, the determined second vector and thedetermined third vector that identifies a location of the microphoneoutside of the threshold location, and determine the location of themicrophone relative to the one or more transducers based on theremaining two of the determined first vector, the determined secondvector and the determined third vector.
 44. The non-transitorycomputer-readable storage medium of claim 40, wherein the transducersare arranged as an array of transducers such that each of thetransducers in the array face the same direction, wherein thenon-transitory computer readable storage medium has further storedthereon instructions that, when executed, cause one or more processorsto: process the first ultrasound signal prior to providing the firstultrasound signal to the transducers in the array so as to generate afirst directional ultrasound signal that, when emitted by thetransducers in the array, appears to be directed in a first direction;process the second ultrasound signal prior to providing the secondultrasound signal to the transducers in the array so as to generate asecond directional ultrasound signal that, when emitted by thetransducers in the array, appears to be directed in a second direction;and concurrently provide the first and second directional ultrasoundsignals to the transducers in the array such that the transducers in thearray concurrently emit the first and second direction ultrasoundsignals as the first and second ultrasound signals.
 45. Thenon-transitory computer-readable storage medium of claim 40, wherein themicrophone is included within or adjacent to three-dimensional viewingglasses, wherein the one or more transducers are included within oradjacent to a three dimensional display device, and wherein thenon-transitory computer readable storage medium has further storedthereon instructions that, when executed, cause one or more processorsto: select one of a plurality of views included within video data thatapproximates viewing a scene presented by the video data from a relativelocation similar to that determined location of the microphone relativeto the one or more transducers; and present the selected one of theplurality of views.
 46. The non-transitory computer-readable storagemedium of claim 40, wherein the microphone comprises one of a pluralityof microphones, each of which is associated with a different student;wherein the instructions that, when executed, cause the one or moreprocessors to determine the location further comprise instructions that,when executed, to determine the location of each of the plurality ofmicrophones relative to the one or more transducers, wherein thenon-transitory computer readable storage medium has further storedthereon instructions that, when executed, cause one or more processorsto: generate an image that depicts the determined location of each ofthe microphones as the location of the associated students relative toone another and the one or more transducers and that specifies studentinformation proximate to the location of each of the associatedstudents; and present the generated image.
 47. The non-transitorycomputer-readable storage medium of claim 40, wherein the microphonecomprises one of a plurality of microphones, each of which is associatedwith a different customer, wherein the one or more transducers comprisetwo or more transducers placed with respect to a seat in which thedifferent customers are able to sit, wherein the instructions that, whenexecuted, cause the one or more processors to determine the locationfurther comprise instructions that, when executed, to determine thelocation of each of the plurality of microphones relative to the one ormore transducers, and wherein the non-transitory computer readablestorage medium has further stored thereon instructions that, whenexecuted, cause one or more processors to: determine that the differentcustomers have sat in the seat based on the determined location of eachof the plurality of microphones; and present an image via a display inresponse to determining that the different customers have sat in theseat.